At a distance of `5 cm and 10 cm` outward from the surface of a uniformly charged solid sphere, the potentials are `100 V and 75 V`, repectively. Then.

Options

A. `(1/3) xx10^(-9) C`
B. `(2/3)xx10^(-9) C`
C. `(5/3) xx10^(-9)C`
D. `(7/3)xx10^(-9)C`

Answer

C

Explanation

`(kQ)/((r+5 cm))=100 V, (kQ)/((r+10 cm))=75 V`
`:. Q=5/3 xx10^(-9) C, r=10 cm`
`:. V_("surface")=(kQ)/2=150 V E_("Surface")=(kQ)/(r^(2))=1500 V//m`
`V_("centre")=3/2 V_("surface")=3/2xx150 =225 V`